The metabolic clearance rate (MCR) and hepatic and extrahepatic extraction of progesterone will be studied. The uterine extraction of progesterone, estradiol and estrone and the uterine interconversion of estrogen and androgens and the uterine conversion of progesterone to 20 alpha-hydroxypregn-4-en-3-one (20 alpha-OHP) and androgens to menstrual cycle. These studies will be extended to cases of endometrial hyperplasia and adenocarcinoma of the endometrium. The significance of the circulating concentration of cortisol, which competes with progesterone for transcortin binding, on the MCR of progesterone in women during the menstrual cycle, the third trimester of pregnancy and during labor will be evaluated. The effect of acute and chronic progestin administration on the MCR of progesterone will also be studied. These studies are being extended to Rhesus monkeys where hepatic and extrahepatic extraction of progesterone are being studied in the presence of varying concentrations of progesterone or transcortin. The in vivo distribution of transcortin is being studied. These studies will be extended to testing whether or not transcortin can associate with uterine endometrial cells in vitro. BIBLIOGRAPHIC REFERENCES: Rahman, S.S., Billiar, R.B., and Little, B., The Plasma Level of 5 alpha-DHP After Intramuscular Injection of 5 alpha-DHP and The Induction of Uteroglobin in Ovariectomized Rabbits. Biology of Reproduction. 14: 416-420, 1976. Johnson, W.A., Billiar, R.B., Rahman, S.S., and Little, B., The Head Extractions, Brain and Pituitary Uptake and Metabolism of Progesterone and 5 alpha-Dihydroprogesterone in Anesthetized, Female Rabbits. Brain Research. 111: 147-155, 1976.